[alt-photo] Re: platinum

[Paul Viapiano]

Loris,

I remember you saying you liked Hcl better than oxalic acid because it left the paper smoother or less grainy feeling...?

Hmmm, I've never used it but am interested in trying. So, btw 25-40 ml per liter is the range I'm seeing here, assuming I get the dilution sold at a pool supply store here in the US.

How much washing needs to be done after the soak?

Paul

On Feb 15, 2013, at 12:39 PM, Loris Medici <mail at loris.medici.name> wrote:

> Similar here, I remember using 25ml per 1000ml (~0.5M) which was more
> than enough for many many sheets. Just for the records; 1000ml of 0.1M
> solution can dissolve about 5g CaCO3...
> 
> Regards,
> Loris.
> 
> 
> On 15 Şub 2013, at 17:54, Marek Matusz <marekmatusz at hotmail.com> wrote:
> 
>> 
>> Chris,
>> 
>> I have to correct myself! After reading your post I went back to look at my notes. I started with half a liter solution and 20cc muratic acid, but that was too little solution in my big tray to cover the paper, so I kept adding water and acid until I had about 2 liters, somewhere along the line my calculation went off, but looking at it again, I ended up with a 40cc/liter (or about 1.5%). Solution of this concentration should be safe to work with and handle. I would agree that mixing stock solution from concentrated acid is propably not a good idea in a large group of sudents.
>> 
>> I treated about 6-10 sheets (I wish I was better in my notekeeping here) of full size paper with my 2 liter solution. As long as you can see bubbling you are OK on the acid.
>> 
>> Marek
>> 
>> 
>>> From: christinazanderson at gmail.com
>>> Date: Fri, 15 Feb 2013 07:36:40 -0700
>>> To: alt-photo-process-list at lists.altphotolist.org
>>> Subject: [alt-photo] Re: platinum
>>> 
>>> Marek,
>>> 
>>> This is about a 0.75% solution, correct (muriatic acid is 37%?)? I've heard as low as 2% hydrochloric acid but you seem to feel that even lower does the trick?
>>> 
>>> It would be nice to just use one paper (FAEW) in the dimroom but there is no way I could control muriatic acid in the dimroom with a bunch of students unless I mixed up a gallon myself for them, especially since a student in a beginning class has filed a Risk and Safety complaint because another student splashed a drop of fixer in his eye. If this becomes an issue (fixer) you never know what else will be scritinized...
>>> 
>>> This is a very low dilution and seems quite doable, though!
>>> 
>>> How long does it last/how many pieces of paper per liter?
>>> 
>>> I do so love FAEW paper.
>>> 
>>> Chris
>>> 
>>> Christina Z. Anderson
>>> christinaZanderson.com
>>> 
>>> On Feb 14, 2013, at 8:54 PM, Marek Matusz wrote:
>>> 
>>>> 
>>>> Paul, 20cc acid to 1 liter of water. place dry sheets of paper and wait for bubbles to go away, maybe 2-3 minutes. After a couple of sheets I just add more acid. If you don't get any bubbles the acid bath is exhausted. Wash the paper with plenty of water to remove the acid. Marek
>>>>> From: viapiano at pacbell.net
>>>>> Date: Thu, 14 Feb 2013 12:51:56 -0800
>>>>> To: alt-photo-process-list at lists.altphotolist.org
>>>>> Subject: [alt-photo] Re: platinum
>>>>> 
>>>>> Marek,
>>>>> 
>>>>> What dilution and for how long do you treat with the acid?
>>>>> 
>>>>> P
>>>>> 
>>>>> On Feb 14, 2013, at 10:32 AM, Marek Matusz <marekmatusz at hotmail.com> wrote:
>>>>> 
>>>>>> 
>>>>>> 
>>>>>> Here is another something on palladium/platinum papers.
>>>>>> 
>>>>>> 
>>>>>> A couple of months ago I acid treated some Fabriano Artistico sot press. My acid treatment was HCl (hydrochloric or muratic acid). Very inexpensive from pool supply store. This treatment completely removes carbonate buffer leaving just pure paper. I have to say it is one of the best palladium papers that I have used in a while. This treated Fabriono resembles COT 320 in many ways. Beautiful DMAX, and just the right absorbency. Because of the pretreatment (in the old days I would call it pre-shrinking, but now to me it is just getting it wet and do the shrinking /stretching that it wants) step it is very easy to do a gum over the palladium layer.
>>>>>> 
>>>>>> Marek
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